Abstract : Arsenic is a toxic trace element occurring in natural waters in a variety of forms including soluble, particulate and organicbound,but mainly as inorganic trivalent As(III) and pentavalent As(V) oxidation states. In many parts of the world,groundwater is polluted with arsenic. This pollution can be caused by human activities (mining, pesticides...) but usually, themain source of arsenic is geogenic. Epidemiological studies have demonstrated a significant increase in the risks of cancersassociated with high levels of arsenic in drinking water. Consequently, in the case of arsenic, the European standard level indrinking water has been lowered to 10 µg/L and similar reductions in arsenic levels have been adopted elsewhere, includingthe USA. The aim of this study was to develop new and reliable methods to analyse arsenic even at low concentrations, andsimple removal techniques, easy to handle and to apply to low-flow drinking production plants (flow rate < 10 m3/h).As(III) and As(V) adsorption was studied, first on iron (oxy)hydroxides then on pillared clays : a montmorillonite modifiedwith iron, titanium and aluminium polycations. Adsorption was carried out under various experimental conditions. It appearedthat arsenic was better adsorbed on iron (oxy)hydroxide. Yet, iron pillared clay was the only media which could beregenerated.Speciation being a preponderant factor in adsorption, As(III) oxidation study is of great importance. Different commonreagents used for As(III) oxidation were studied: H2O2, NaOCl, FeCl3, KMnO4 and MnO2(s). In order to test their efficienciesthrough As(V) determination, a colorimetric method was developed, based on phosphate measurement. The results showedthat the oxidants which could easily be applied to low-flow drinking production plants were FeCl3 and KMnO4. Thereafter, apolystyrene resin loaded with manganese oxide was synthesised. This solid presents simultaneous oxidation and adsorptionbehaviour, and its adsorption capacities towards As(III) and As(V) were above many studied adsorbents.The last part of this study allowed us to work closer to natural conditions, through the preparation of an artificial water ofgranitic type, such are waters usually polluted with arsenic. The compilation of major ions common concentrations led to thepreparation of a model water, spiked with As(III) or As(V), and used to validate our analysis methods and removalmechanisms. The results proved that the major ions did not have any influence on these processes, showing their possible usein a low-flow drinking production plant.